Wireless networks transmit and receive information utilizing varying techniques and protocols. For example, but not by way of limitation, two common and widely adopted techniques used for communication are those that adhere to the Institute for Electronic and Electrical Engineers (IEEE) 802.11 standards such as the IEEE 802.11n standard, the IEEE 802.11ac standard, the IEEE 802.11ax standard.
The IEEE 802.11 standards specify a common Medium Access Control (MAC) Layer which provides a variety of functions that support the operation of IEEE 802.11-based Wireless LANs (WLANs) and devices. The MAC Layer manages and maintains communications between IEEE 802.11 stations (such as between radio network interface cards (NIC) in a PC or other wireless device(s) or stations (STA) and access points (APs)) by coordinating access to a shared radio channel and utilizing protocols that enhance communications over a wireless medium.
IEEE 802.11ax is the successor to IEEE 802.11ac and is proposed to increase the efficiency of WLAN networks, especially in high density areas like public hotspots and other dense traffic areas. IEEE 802.11ax also uses orthogonal frequency-division multiple access (OFDMA), and related to IEEE 802.11ax, the High Efficiency WLAN Study Group (HEW SG) within the IEEE 802.11 working group is considering improvements to spectrum efficiency to enhance system throughput/area in high density scenarios of APs (Access Points) and/or STAs (Stations).
IEEE 802.11ac supports high physical data rate using a wider channel bandwidth (i.e. 80 MHz or optionally 160 MHz). However, due to the propagation loss, a STA at the edge of the coverage area of a basic service set (BSS) cannot support 80 MHz transmission/reception. Therefore, the physical data rate to a cell-edge STA (CE STA) is much lower than that to the non-cell-edge STA (non-CE STA). For example, in an environment with four access points (APs) located at the four corners of a large 40 m×40 m room, a STA will follow the rules defined in IEEE 802.11 specification to connect with the nearest AP. The physical data rate to the STA in the middle of the room is much lower than that for a second STA near one of the four corners, where the STA is closer to the AP.
A Coordinated Multi-Point (CoMP) strategy, which performs joint precoding among coordinated APs to mitigate the inter-cell interference, is considered as one solution to improve the performance of CE STAs. However, each link between an AP in the CoMP BSS and the CE STA can have different Signal to Noise Ratios and other unique signal characteristics. Thus, specific modulation and coding schemes (MCS) for each link may be needed to best optimize the separate links for data transmission. However, if each AP selects a tailored MCS, the CE STA will need to obtain the MCS information to receive the data properly. There is no procedure currently to provide the MCS information from each AP to the CE STA.